refactor(ext-oidc): replace auth modules with security extensions

2026-09-16 15:54:19 +00:00
parent 017c2443f4
commit e0795299fc
126 changed files with 2944 additions and 5130 deletions
@@ -0,0 +1,17 @@
+package dev.relism.flash.ext.security.apikey;
+
+import java.time.Instant;
+
+/**
+ * An API key as the application stores it: never the secret, only its hash, and the grant it was
+ * issued with — whatever the application authorizes on.
+ *
+ * @param expiresAt {@code null} for a key that does not expire
+ * @param revokedAt {@code null} for a key that has not been revoked
+ */
+public record ApiKey<G>(String id, String secretHash, G grant, Instant expiresAt, Instant revokedAt) {
+
+    boolean isActive() {
+        return revokedAt == null && (expiresAt == null || expiresAt.toEpochMilli() > System.currentTimeMillis());
+    }
+}
@@ -0,0 +1,97 @@
+package dev.relism.flash.ext.security.apikey;
+
+import dev.relism.flash.ext.security.AuthenticationFailedException;
+import dev.relism.flash.ext.security.AuthenticationMechanism;
+import dev.relism.flash.ext.security.Principal;
+import dev.relism.flash.ext.security.SecurityExtension;
+import dev.relism.flash.ext.security.SecurityScheme;
+import dev.relism.flash.extension.FlashContext;
+import dev.relism.flash.extension.FlashExtension;
+import dev.relism.flash.extension.FlashRegistrar;
+import dev.relism.flash.models.Request;
+
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+import java.util.Base64;
+
+/**
+ * API keys sent as {@code Authorization: Bearer <prefix>_<id>.<secret>}. The prefix makes a key
+ * recognisable at a glance and to secret scanners; the id is what the store is queried by; only a
+ * SHA-256 of the secret is ever stored — a KDF would add nothing to 192 random bits.
+ *
+ * <pre>{@code
+ * app.install(new SecurityExtension())
+ *    .install(new ApiKeyExtension<>("gk", keys::find));
+ * }</pre>
+ */
+public final class ApiKeyExtension<G> implements FlashExtension, AuthenticationMechanism {
+
+    private static final AuthenticationFailedException INVALID = new AuthenticationFailedException("Bearer error=\"invalid_token\"");
+    private static final SecureRandom RANDOM = new SecureRandom();
+    private static final Base64.Encoder BASE64URL = Base64.getUrlEncoder().withoutPadding();
+
+    private final String prefix;
+    private final String bearer;
+    private final ApiKeyStore<G> store;
+
+    /** @param prefix identifies this application's keys; letters and digits only */
+    public ApiKeyExtension(String prefix, ApiKeyStore<G> store) {
+        if (!prefix.matches("[A-Za-z0-9]+")) throw new IllegalArgumentException("API key prefix must be alphanumeric: " + prefix);
+        this.prefix = prefix;
+        this.bearer = "Bearer " + prefix + "_";
+        this.store = store;
+    }
+
+    /** A new key: 72 bits of id, 192 bits of secret. */
+    public GeneratedApiKey generate() {
+        String id = random(9);
+        String secret = random(24);
+        return new GeneratedApiKey(id, prefix + "_" + id + "." + secret, hash(secret));
+    }
+
+    @Override
+    public Principal authenticate(Request req) {
+        String header = req.header("Authorization");
+        if (header == null || !header.startsWith(bearer)) return null;
+        int dot = header.indexOf('.', bearer.length());
+        if (dot < 0) throw INVALID;
+        ApiKey<G> key = store.find(header.substring(bearer.length(), dot));
+        if (key == null || !matches(header.substring(dot + 1), key.secretHash()) || !key.isActive()) throw INVALID;
+        return new ApiKeyPrincipal<>(key.id(), key.grant());
+    }
+
+    @Override
+    public SecurityScheme scheme() {
+        return SecurityScheme.bearer("apiKey", prefix + "_<id>.<secret>");
+    }
+
+    @Override
+    public void configure(FlashRegistrar<?> app, FlashContext ctx) {
+        ctx.provide(ApiKeyExtension.class, this);
+        ctx.onReady(() -> ctx.require(SecurityExtension.class).mechanism(this));
+    }
+
+    private static boolean matches(String secret, String secretHash) {
+        return MessageDigest.isEqual(digest(secret), Base64.getUrlDecoder().decode(secretHash));
+    }
+
+    private static String hash(String secret) {
+        return BASE64URL.encodeToString(digest(secret));
+    }
+
+    private static byte[] digest(String secret) {
+        try {
+            return MessageDigest.getInstance("SHA-256").digest(secret.getBytes(StandardCharsets.US_ASCII));
+        } catch (NoSuchAlgorithmException impossible) {
+            throw new IllegalStateException(impossible);
+        }
+    }
+
+    private static String random(int bytes) {
+        byte[] value = new byte[bytes];
+        RANDOM.nextBytes(value);
+        return BASE64URL.encodeToString(value);
+    }
+}
@@ -0,0 +1,6 @@
+package dev.relism.flash.ext.security.apikey;
+
+import dev.relism.flash.ext.security.Principal;
+
+/** A caller authenticated by an API key, carrying the grant the key was issued with. */
+public record ApiKeyPrincipal<G>(String name, G grant) implements Principal {}
@@ -0,0 +1,9 @@
+package dev.relism.flash.ext.security.apikey;
+
+/** Where the application keeps its API keys. */
+@FunctionalInterface
+public interface ApiKeyStore<G> {
+
+    /** The key with this id, or {@code null}. */
+    ApiKey<G> find(String id);
+}
@@ -0,0 +1,7 @@
+package dev.relism.flash.ext.security.apikey;
+
+/**
+ * A freshly generated key. {@code token} goes to the caller exactly once; the application stores
+ * {@code id} and {@code secretHash}, never the token.
+ */
+public record GeneratedApiKey(String id, String token, String secretHash) {}
@@ -0,0 +1,57 @@
+package dev.relism.flash.ext.security.apikey;
+
+import dev.relism.flash.ext.security.SecurityExtension;
+import dev.relism.flash.ext.security.SecurityIdentity;
+import dev.relism.flash.ext.security.SecurityPolicy;
+import dev.relism.flash.testing.FlashTest;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import java.time.Instant;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+class ApiKeyExtensionTest {
+
+    static final Map<String, ApiKey<String>> KEYS = new ConcurrentHashMap<>();
+    static final SecurityExtension security = new SecurityExtension();
+    static final ApiKeyExtension<String> apiKeys = new ApiKeyExtension<>("fk", KEYS::get);
+
+    @RegisterExtension
+    static final FlashTest app = FlashTest.of(flash -> flash
+            .install(security)
+            .install(apiKeys)
+            .get("/grant", (req, res) -> SecurityIdentity.current().principal(ApiKeyPrincipal.class).grant(),
+                    security.enforce(SecurityPolicy.AUTHENTICATED)));
+
+    static String issue(String grant, Instant expiresAt, Instant revokedAt) {
+        GeneratedApiKey key = apiKeys.generate();
+        KEYS.put(key.id(), new ApiKey<>(key.id(), key.secretHash(), grant, expiresAt, revokedAt));
+        return "Bearer " + key.token();
+    }
+
+    @Test
+    void anIssuedKeyAuthenticatesWithItsGrant() {
+        app.request().header("Authorization", issue("project-42", null, null)).get("/grant").expectStatus(200).expectBody("project-42");
+    }
+
+    @Test
+    void aWrongSecretAnExpiredKeyAndARevokedKeyAreRejectedAsInvalid() {
+        String valid = issue("x", null, null);
+        for (String token : new String[]{
+                valid.substring(0, valid.length() - 1) + (valid.endsWith("A") ? "B" : "A"),
+                issue("x", Instant.now().minusSeconds(1), null),
+                issue("x", null, Instant.now()),
+                "Bearer fk_no-secret-here"}) {
+            app.request().header("Authorization", token).get("/grant")
+                    .expectStatus(401).expectHeader("WWW-Authenticate", "Bearer error=\"invalid_token\"");
+        }
+    }
+
+    /** Another application's bearer token is not a key of ours: it is left to other mechanisms, not rejected. */
+    @Test
+    void aForeignBearerTokenIsNotThisMechanisms() {
+        app.request().header("Authorization", "Bearer eyJhbGciOi.payload.signature").get("/grant")
+                .expectStatus(401).expectHeader("WWW-Authenticate", "Bearer realm=\"apiKey\"");
+    }
+}